Valve for rock drills



1929. F. w. RUDLIN 1,711,811

VALVE FOR ROCK DRILLS Filed Nov. 5, 1926 IN V EN TOR. Z1

2 I v I v ,V 1

HIS/1 TTNEY Patented May 7, 1929.

UNETED STATES rnnnnnrox w. RUDLIN, or rnILLIrsBUne, NEW JERSEY, Assrenon T0 rivennsonn- RAND COMPANY, or JERSEY CITY, nnw JnnsnY, A coaronnrron or new Jinasnr.

' Application filed November This invention relates to rock drills, but more particularly to a. distributing valve of the spool type for fluid actuated rock drills.

The objects of this invention are to obtain an inlet valve which is quick and positive arrangement of parts having the general mode of operation substantially as hereinafter described and more particularly pointed out in the appended claims, and illustrated in the accompanying. drawings, in

which s Figure 1 is a longitudinal sectionalelevation showing the relative position of the moving parts when the piston is on its working stroke, and

Figure 2 is a similar view showing the relative positions of the moving parts when the piston is on its return stroke. a

. Referring more particularly to the drawings, the invention is shown embodied in a rock drill having a cylinder A, within which is a reciprocatory hammer'piston B having a forward extension or nose C which cooperates slidably with a front cylinder washer D seated in the front end of the cylinder A to form. a closure therefor. The rearward end of the cylinder is in this instance sealed by a back head E.-

The back head E is shown solid and the nose C of the piston B is shown as a plain extension for the sake of simplicity of illustration.

In the present instance a valve chest F has a bore to receive hushings p and-0, which form avalve chamber G of uniform diameter throughout its length. The valve chest. F is preferably arranged longitudinally of the cylinder A and has an inlet connection H for the admission of pressure fluid to the chamber G from a source of pressure fluid supply. The valve chest F may be either formed integrally with the cylinder A or may be formed separately and secured in position in any suitable manner.

The chamber G is in this instance of uniform diameter throughout its length and is open at its ends to receive sealing plugs J and VALVE FOR ROCK DRILLS.

5, 1826. Serial no. 146,359.

K, which may be held securely in place in any suitable manner.

Communication between the front and rear ends of the cylinder A and the chamber F is afforded by ports L and O which act as inlet and exhaust ports alternately. Within the chamber F is a pressure fluid distributing valve P having a reduced central portion Q, and end heads R and S which have actuating faces T and U respectively at their outer ends against which pressure fluid may act to throw the valve in a manner to be de scribed hereinafter.

' The travel of the valve is limited by the stops J and K against which the actuating faces T and U of the valve may strike. Be-

tween the chamber G and the cylinder bore 7 A are provided passages V, W, X and Y which cooperate with the valve P and the piston B in a manner-to be hereinafter described. Kicker ports Z and a are located intermediate the ports L and O. The ports W and X are so spaced with respectt-o each other that both may not be covered by the valve P simultaneously.

In the operationof the drill, with the valve P in the position indicated in Figure 1, the passages W and Y will be uncovered by the heads Rand-Srespectively of the valve-P. l/Vhen the valve is in this position, pressure fluid will flow from the chamber G through-thepassageVV'and the port L and into the rearward end of the cylinder bore A im-pelling the piston forwardly. At the same time, pressure fluid. is being exhausted from the forward end ofthe cylinder by way of the port 0 and the passage Y to the admitting pressure fluid to the forward end of the cylinder A and the piston B is forced to the rear, due to the pressure on its forward face. The pressure fluid in the rearward end of the cylinder passes through port L, passage V and to the atmosphere through exhaust port g. As soon as the port as is uncovered by the piston, live pressure fluid is admitted to an annular passage 6 and into a chamber where the face U of the valve P is exposed to the pressure fluid and the valve is thrown rearwardly covering passages V and X and opening passages Y and W, thus completing the cycle of operations.

The ports L and Q are so placed with respect to the ends of the cylinder that a sufficient quantity of air is trapped by the piston on either its forward or its backward stroke to form a cushion for the piston. In normal operation, this air cushion overcomes the inertia of the piston in one direction and returns it in the opposite direction a sufficient distance to bring it under the control of the ports 0 or L as the case may be. If, however, the tool is allowed to stand idle for sometime the piston may take up a position too far forward or rearward to be under control of the ports O or L. To meet such a contingency, scratch passages 70 and. 7c are provided as shown whereby pressure fluid may be admitted to either face of the piston in order to return it to an operative position.

I claim:

1. In a rock drill, the combination of a cylinder, a hammer piston in the cylinder, a valve chest having a chamber, a valve in the chamber having a head'at each end, an inlet port for admitting pressure fluid to the chamber between the heads, supply and exhaust passages leading from the chamber to the ends of the cylinder, said supply and exhaust passages being controlled by the heads, and kicker ports in the valve chest conveying pressure fluid from the cylinder to the ends of the chamber for actuating the valve.

2. In a rock drill, the combination of a cylinder, a hammer piston in the cylinder, a valve chest having a chamber of uniform diameter throughout'its length, a valve in the chamber having a head at each end, an inlet port for admitting pressure fluid to the chamber between the heads, supply and exhaust passages leading from the chamber to the ends of the cylinder, said supply and exhaust passages being controlled by the end heads, and kicker ports 1n the valve chest leading from the cylinder to the ends of the valve chamber for conveying pressure fluid -to the said ends of the valve chamber for diameter throughout its length, a valve in the chamber having a head at each end, an inlet port for admitting pressure fluid to the chamber between the heads, 'supi ily passages leading from the chamber to the ends of the cylinder, exhaust passages leading from the supply passages to the ends of the chamber, exhaust ports in the ends of the said chamber leading to the atmosphere, said supply and exhaust passages being controlled by the end heads of the valve, a kicker port leading from the front end of the cylinder to the front end of the valve chamber, and a second kicker port leading from the rear ard end of the cylinder to the rearward end of the valve chamber for conveyin pressure fluid to the ends of the valve chamber to act against the ends of the heads for actuating the valve. i

4t. In a rock drill, the combination of a cylinder, a hammer piston in the cylinder, a valve chest having a chamber, a valve in the chamber having a pair of end heads, an inlet port for admitting pressure fluid to the chamber between the heads, supply passa es leading from the chamber to the ends of the cylinder, exhaust passages leading from the supply passages to the endsof the chamber, exhaust ports in the ends of the said chamber leading to the atmosphere, said sup ply and exhaust passages being controlled by the end heads of the valve, a kicker port leading from the cylinder to the front end of the valve chamber, a second kicker port intermediate the first-said kicker port and the rearward supply port leading to the rearward end of the valve chamber for conveying pressure fluid to the said ends of the valve chamber for actuating the valve, said end heads of the valve controlling communication between the exhaust ports and the valve chamber ends of the kicker ports.

In testimony whereof I have signed this specification.

FREDERICK W. RUDLIN. 

